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BQ24600: How to limit the maximum charge to 0.1C while the less than 10°C?

Sidney Aaronovitch
Prodigy 10 points
Part Number: BQ24600

Hi,

I'm looking to the IC BQ24600 to charge a Li-ion battery at 5A, however, I want to limit the charge to 0.1C while the IC is operating from 0-10°C?

The datasheet is not completely clear to me how I might achieve this, or if it's even possible with this IC without 'fudging' additional circuits.

Support on how this may be achieved?

Thanks,

SA

 

  • 0
    TI__Mastermind 24075 points

    Hi Sidney,

        ISET controls the fast charge current, when BQ24600 is in the CC phase of charging. If you are using a thermistor at TS so that voltage sensed at TS corresponds to the battery temperature, you can use the following steps:

    • Select TCOLD and TCUTOFF, and size your resistors according to equation 5 and 6 in the datasheet, based off of your thermistors resistance
      • This will stop charging if T<TCOLD and T>TCUTOFF
    • Calculate the voltage at TS that corresponds to 10C
    • Use a comparator to drive the gate of a FET. This FET can be used to change the parallel resistance of the ISET bottom resistor which would change your charge current, in the 0C-10C range

    As BQ24600 precharge current is already 1/10 of fast charge, there is no issue when battery is in precharge.